In recent years, an imprinting method has been proposed as a method for forming a fine pattern on a workpiece such as a semiconductor substrate. In this imprinting method, a mold (master) having a concavo-convex pattern formed thereon is pressed against the surface of a liquid material to be transferred (for example, photocurable resin) such as a resist applied on a workpiece. Then, light is irradiated from the surface opposite to the surface on which the pattern is formed, and the mold is removed from the cured material to be transferred. Thereby, the concavo-convex pattern is transferred to the material to be transferred. A template is used as a mold to be pressed against the surface of the liquid material to be transferred. This template is also called mold, imprint mold or stamper.
The template is formed of quartz or the like having high translucency so that light such as ultraviolet rays is easily transmitted in a step (transfer step) of curing the material to be transferred. The template is provided with a convex portion (convexity) on its main surface, and a concavo-convex pattern to be pressed against the liquid material to be transferred is formed on the convex portion. For example, the convex portion having a concavo-convex pattern is referred to as “mesa portion”, and a portion other than the mesa portion on the main surface of the template is referred to as “off-mesa portion”.
However, when the template is pressed against the liquid material to be transferred, the liquid material to be transferred seeps out from the end of the convex portion. Although it is a small amount, the liquid material to be transferred having seeped out may sometimes be raised along the side surface (side wall) of the convex portion. The material to be transferred adhering to the side surface of the convex portion is cured in that state by light irradiation. Accordingly, when the template is separated from the material to be transferred, a raised portion is present in the material to be transferred, resulting in the occurrence of pattern abnormality.
In addition, when the template is separated from the material to be transferred, the raised portion of the material to be transferred sticks to the template. It thereafter may drop on the material to be transferred at some timing and become dust. If the template is pressed onto the dropped dust, the concavo-convex pattern on the template may be damaged, or the dropped dust enters in the concavo-convex pattern on the template and becomes foreign matter. Thus, template abnormality occurs. Further, if pattern transfer is continuously performed using a template having such a damaged concavo-convex pattern or a template into which a foreign matter has entered, a defect is generated in the pattern of the material to be transferred, thus resulting in the occurrence of pattern abnormality.